The present invention relates to a handrail for a walkway with acceleration for conveying people or materials, which offers major improvements in user comfort and in the simplicity of its mechanism.
More specifically the handrail of the invention is of the type which comprises a system of handles which circulate over the length of the walkway, with a forward stretch and a return stretch, mounted on a drive mechanism. Diverse handrail systems are already known for variable speed walkways. For example, a system consisting of several handrails at constant speed is known, in which each handrail circulates at a speed different from the previous one, as close as possible to that of the plates that are in the same area. Handrails with this constitution are described for example in the French patent 2757143 and in the European patent no 0837026.
Systems are also well-known that are made up of pieces or handles that circulate at the same speed as the neighboring plate. Speed variation can be achieved by means of the use of variable speed chains, such as is described in the patent GB 2264686, by means of elements linking the pieces, which employ appropriate guides to enable the speed to be varied, such as is described in the patent FR 2792626, or by means of systems of friction as is described in the U.S. Pat. No. 4,232,776.
EP 0831052 discloses a continuous variable speed handrail formed by a rubber belt with a reticular cable structure in its interior. Speed variation is achieved by deforming the rubber belt perpendicular to the movement direction.
In all cases the handrails require some relatively complicated mechanisms and the effect achieved does not always adapt to the speed of the corresponding stretch of the walkway with acceleration.
The object of the present invention is to develop a handrail for a variable speed moving walkway which is of simple constitution and which allows speeds to be obtained over the forward stretch of the handrail appropriate for or coordinated with those of the stretch of the corresponding walkway.
The handrail of the invention is characterized in that the profile or belt which forms the handrail proper is constituted on a basis of fixed and variable length stretches, alternating and linked to each other, the fixed length stretches having internally a profile which defines a toothed arrangement which meshes successively with a series of drive chains which are arranged between the forward and return stretches of the handrail and which are mounted between toothed wheels, each one of these chains moving at a speed different from the adjacent chains. The chains are driven by guides which determine transition areas of the fixed length stretches between two consecutive chains of different speed.
In another possible configuration, the handrail would be constituted by a great many fixed length stretches, separated from each other by variable distances as a function of the area of the walkway in which they are located, and having on their lower part a profile identical to that described previously.
The adjacent toothed wheels of each two consecutive chains have a different diameter and a different number of teeth and are mounted on a same axle, the two wheels abutting against each other, so that the corresponding chains run on close and parallel planes. This constitution allows the use in the whole system of a single drive shaft which will transmit the movement to the remaining chains, in a coordinated manner, the increase or decrease of speed thereof taking place according to the tooth ratio between two consecutive wheels.
The aforementioned guides run immediately inside the flexible belt or profile which forms the handrail and define, at least in the transition area, two parallel longitudinal paths, through each of which circulates one of the chains which converge on said area, between which penetrates the toothed profile of the fixed length stretches of the handrail.
In the transition areas means can also be mounted for pushing on the fixed length stretches which produce a speed variation of said stretches in the same direction as the movement in said area.
In the area where the user boards, the fixed pieces are meshed in a chain running at slow speed, approximately equal to the speed of the system for moving people on the walkway in that area. The meshing takes place between two points of the fixed length stretches and two points of the chain. In a preferred configuration, each fixed length stretch would have a rack type profile with two valleys, meshed with two elements of revolution located on two articulations of the chain.
In the area of acceleration, each fixed length stretch is meshed with different chains each of which circulates at a greater speed than the previous one. Thus, each fixed length stretch maintains a speed close to the speed of the system for moving people in said area. The transition of each fixed length stretch between two consecutive chains is carried out in the following way:
Initially each fixed length stretch comes meshed in two articulations of one chain as was described previously. The element of the chain which is in the first articulation disengages from the fixed length stretch by the use of some appropriate guides for the chain. This allows the higher speed chain to mesh in the hole that the first articulation of the lower speed chain has left free. Simultaneously, and due to the configuration of the guides of each chain, the second articulation of the lower speed chain disengages from the fixed length stretch. Finally, the second articulation of the higher speed chain meshes in the hole that the second articulation of the lower speed chain has left free. The design of the rack of each fixed length stretch, and the relative position of the chains, guaranteed by the guides thereof, allows these meshing actions to be carried out such that a fixed length stretch is never loose, nor is it jammed due to the different speeds of the chains.
In the preferred configuration, the movement of the higher speed chain is transmitted to the lower speed chain on an axle close to where the transition is performed, which has two toothed wheels with a different number of teeth.
The transitions of the fixed length stretches between the different chains are carried out in an improved manner by using two variable speed conjugate profiles; one belonging to the fixed length stretch, and the other belonging to a special toothed wheel which rotates with the shaft that moves the two aforementioned chains. Thus the speed variation is smoother, improving user comfort and the life of the elements.
This same effect can be achieved with other systems; for example, by using a cam and a pusher that are synchronized with the movement of the chains. This transition described above is repeated as often as is necessary to increase the speed until maximum speed is reached.
In the area of maximum speed, each fixed length stretch meshes with a maximum speed chain.
The deceleration takes place in the same way as that described previously for the acceleration, although on this occasion, the chain which leaves the fixed length stretch is that of higher speed, and the chain that meshes is that of lower speed.
In the exit area, the handrail fixed length stretches circulate at slow speed, meshed with a slow speed chain, close to the speed of the system for moving people in that area. The turn-around is also produced of the fixed length stretches, starting the return path, which is carried out in the same way as that described for the working part; namely, first accelerating, circulating afterwards at maximum speed, and finally decelerating, to turn around once again and recommence the cycle described previously.
In the configuration with extendable elements, these adapt their length in each area as a function of the relative position of the two consecutive fixed length stretches to which there are joined.
In the configuration without extendable elements, there is a profile on which the handles in the working part slide. This profile is such that it allows the size of the slot connecting the handle with the mechanisms to be diminished, avoiding the users being pinched.
Also, it prevents the objects the user is carrying from catching on the handles. Ideally, this profile prevents the user from seeing the slot. Configurations are possible also with more than one slot, and with slots visible. These slots can be covered with some brushes or a rubber profile.
In this last configuration, the handle in its visible area is of very reduced thickness. This is possible because its strength is achieved due to the aforementioned guide profile. This reduced thickness allows the slot of the safety mechanism of the areas in which the handles are inserted in the hidden part of the machine, to be very small. In the preferred configuration, the guide profile on which the handles run will have its surface slotted. The handle will have some ribs in the form of pins that are inserted in said slots, and in this way pinching is avoided.
With the system described in the present invention, major benefits are obtained:
There are no transitions between handrails, whereby user safety is increased.
The speed variation is obtained with simple mechanisms.
All the characteristics of the invention, such as are to be found in the claims, are explained hereunder in greater detail, based on the attached drawings, wherein an example of embodiment is shown in a non-restrictive manner. In the drawings: